Splined joints are much used in vehicles and other machinery where it is necessary to provide transmission of rotational energy but also to be able to demount or separate the drive train components at a particular point. It has become increasingly common in vehicles to use such splined joints in drive assemblies at the point where the drive axle connects to the hub supporting the drive wheels. The wheel hub is held by bearings attached to the vehicle suspension. The hub rotates freely in response to the drive axle rotation, but is otherwise constrained in orientation by the suspension or the combination of the suspension and steering linkage of the vehicle.
This construction is especially found, for example, in front-wheel drive vehicles or in rear wheel drive vehicles where the differential or transmission is mounted to the car frame and articulated shafts couple to independently suspended drive wheels, or in vehicles providing a combination of front and rear drive. Frequently, an assembly referred to in the art as a constant velocity (CV) joint is located in the drive axle immediately behind the hub and hub support bearings. The axle shaft or the CV joint has an external spline which mates with an internal spline on the inside of the wheel hub, thus providing a demountable rotary connection between the drive train and the wheels of the vehicle or machine. In many vehicles an attachment means, such as for example a threaded extension is provided on the end of the splined shaft for holding the splined shaft and hub together.
In some cases the splines on the shaft and within the wheel hub are tapered and/or have an interference fit so that once assembled there is no slop or movement in the joint. Usually, considerable force is required to install or demount an interference fit splined shaft and hub. In the prior art, the assembly of such a joint could be accomplished by a puller which attached to the threaded extension on the splined shaft and pulled the splined shaft into the wheel hub. However, there has not been any method for demounting such an interference fit splined shaft and hub except by removing the hub from the vehicle and using an arbor press or similar apparatus for forcing the splined shaft out of the hub. Considerable additional labor is required to disassemble the hub from the vehicle for this purpose. Thus, a need continues to exist for an improved tool for demounting splined shafts, particularly interference fit splined shafts used in vehicles, without having to demount from the vehicle the bearing hub containing the outer spline.
Accordingly, it is an object of the present invention to provide an improved tool for quickly and easily demounting splined joints in drive trains of vehicles or machinery, and especially for interference fit joints in front-wheel drive vehicles.
It is an additional object of the present invention to provide a single tool of improved design which permits both mounting and demounting of splined joints without removing the hub holding the splined shaft from the vehicle or machine.
It is a further object of the present invention to provide an improved double acting installation and removal tool for splined joints in the front wheel drive assembly of vehicles.
It is an additional object of the present invention to provide an improved double acting installation and removal too for splined joints in front wheel drive vehicles which is particularly adapted for use with a double acting slide hammer.
As used herein, the words "spline" or "splined" is intended to refer to a shaft which has on its exterior longitudinal grooves and ridges dispersed around the circumference of the shaft, and generally intended to slide into a hollow opening having a mating arrangement of longitudinal ridges and grooves on its interior. As used herein, the word "hub" is intended to refer generally to a part held in an external assembly by bearings which allow free rotation of the part, and which has a central bore which is internally splined to accept a mating external spline on a drive shaft or CV joint to be attached thereto for the purpose of driving the hub. For Example, in a front-wheel drive vehicle, this hub corresponds to the wheel mounting hub supported by bearings in the front suspension and steering mechanism, which is driven by the drive train and to which the front drive wheels are attached.